Search Documents

By Charles Will Wright

FRANCE will be given a large portion of the Marshall Plan funds for relief, reconstruction, and industrial development in France and in her colonial possessions. At present that country is not in position to export any large tonnages of the mineral products needed in the United States. However, if, through Marshall Plan aid and private capital investment, production of these products can be largely increased, agreement should be made by which the United States is to get a substantial portion of such increased output in part payment for the material and technical aid they receive. France issued a decree, published in the "Official Gazette" on Feb. 3, 1948, which permits conversion into dollars of dividends derived from dollar investment in Government-approved projects and will agree to a scale of capital amortization to be determined in each individual case. This decree is to encourage private capital to cooperate with local capital in industrial undertakings. The French Colonial Ministry has prepared an extensive program for aid to the mining industries in overseas possessions to be undertaken by

Jan 1, 1948

By R. Buehl

ALTHOUGH the main features of the transformations occurring in 18-8 have been published already,1-4 certain conclusions merit questioning and discussion. The questions may be summarized as follows: PERCENT REDUCTION BY COLD ROLLING FIG. 1.-VARIATION OF FERRITIC INDUCTION AND PERCENTAGE OF FERRITE WITH COLD REDUCTION. Composition of Alloy: C, 0.08; Mn, 0.40; Si, 0.24; P, 0.014; Cr, 18.13; Ni, 8.94. 1. If ferrite is formed by cold-working austenite, what happens to the carbon with which the ferrite and austenite are both pre-sumably supersaturated? 2. What is the nature of the alpha-ferrite formed at grain boundaries by chromium-carbide precipitation at these boundaries?

Jan 1, 1939

By Milton Fies

ALTHOUGH pig iron from iron ore and red cedar charcoal preceded the mining of coal by many years, for tradition says that Alabama iron was used to shoe the horses of Andrew Jackson's soldiers, coal was not produced until 1830. In that year, coal was mined in Tuscaloosa County, in the vicinity of what is now the University of Alabama, and shipped on flat boats (obviously during the wet season, for there were many shoals) down the Warrior River to Mobile. About that time, the first railroad, the Decatur & Tecumseh, was being constructed in northern Alabama to overcome the obstructions to freight traffic caused by the now well-known Muscle Shoals in the Tennessee River. This railroad was patterned after a railroad at Mauch Chunk, Pa., which was used for hauling anthracite from the Panther Creek valley. The Alabama railroad, which required about four years to complete, was 46 miles long and was used solely for the transportation of cotton. Although it was a failure, it demonstrated the practicability of the undertaking, and the succeeding railroads, which were begun in 1834, 1848, 1852, and 1853, added immeasurably to the development of the coal resources of the state. Between the years 1830 and 1860, practically all the coal mined in the state was dug from the outcrop near the river or from the river beds, and shipped by boat to Mobile. Transporting coal down the Warrior River was one of great risk, required much skill, and frequently had heavy losses. It is recorded that this coal was sold to the gas company in Mobile in 1844; it was most likely mined from the Black Creek Seam. In 1914, on the completion of Lock 17, the Warrior River became a navigable stream from 9 miles above Cordova, Ala., to Mobile and offers a great opportunity for the future development of the coal resources of the state.

Jan 9, 1924

By A. W. Fahrenwald

FLOTATION practice in Idaho is now about 13 years old. The advance has been steady during these 13 years. The operators have been alert to take advantage of the newest developments and they have themselves made a constant effort to improve their work. The metallurgical improvements are clue to the development of (1) better equipment, (2) better reagents, and (3) better understanding and control of the process. During the 8 years which the writer has been in this district, there has been continuous experimentation by several companies to improve the ore dressing by flotation methods. Gravity concentration has fought hard to hold its place, and although it is true that gravity processes have been improved during this period, nevertheless, in several of the important mills of the district the few tables that managed to hang on have finally given way. On the straight-lead ores, tables and jigs are still used; and, due to better classification, their hold on this job has been strengthened.

Jan 1, 1927

By H. C. George

IN 1901, the United States produced 69 million barrels of crude oil, which was 41.4 per cent of the world production. By 1931, these figures were 850 million barrels and 62.1 per cent respectively, showing over this period of thirty years an increase in the world production of 718 per cent. Over this same period, the increase in the demand for technically trained men in the industry was much greater than the increase in crude-oil production. This was because much of the increase in production was secured by the application of geology and physics to the finding of new oil fields and by .the development of engineering methods and equipment incident to drilling and producing from much greater .depths.

Jan 1, 1934

BUMPS in No. 2 Mine, Springhill, N. S., furnished the main feature for discussion at the morning meeting* on Ground Movement and Subsidence on Feb. 18. Walter Herd, the author of the paper by which the discussion was introduced, not being well, was unable to be present. The paper was presented by T. L. McCall, who laid stress on the presence of sand- stone as the cause of bumps, on the value of retreating longwall in eliminating such phenomena at the coal face and on the advantage of wide headings with packs on either side, leaving space behind them for any coal that bumps might dislodge. George S. Rice, who presided, referred to his visits to the Nova Scotia mines and said that bumps usually occurred only where the coal was thick and strong and the roof and floor both more than usually hard. If any of the three were weak, bumps were not likely to occur. In the Nova Scotia mine, to which Mr. Herd referred, there was no material for packwalls and for this reason as well as for safety he had been convinced that long- wall retreating with a small percentage of pack walling was the most feasible plan.

Jan 1, 1929

By J. M. Cases

Study of the normal interaction between flotation collectors and the silicates through measurement of the electrokinetic potential carried out by the streaming potential and flotation recovery methods indicates that the interaction is wholly 07 partly of electrostatic origin. In some cases, it partly consists of the chemical affinity of the polar head of the collector for the active surface sites. Reagents composed of a polar head and a paraffinic chain and forming micelles in solution were used as flotation collectors. They are sodium dodecylsulfate (anionic collector) and dode-cylammonium chloride (cationic collector). The adsorption isotherms on biotite of alkylamine chloride having 10 to 18 carbon atoms in their chain all show a sharp change in slope relevant to the condensation of alkylammonium ions into bidimensional phase.1-1 Condensation is possible because of the relative homogeneity of the adsorbing surface and of the very strong lateral binding forces through Van der Waals type bonds in the adsorption layer. The different isotherms are seen to coincide when, instead of the equilibrium concentration, the under-saturation ?µ = kT In C/C, is plotted in abscissa, C representing the concentration of the solution with which the adsorbed layer is in equilibrium and C, the saturation concentration of micelles in solution or. critical micellar concentration. More particularly, the undersaturation ?,u1*, corresponding to a surface coverage 6 of 0.5, is equal to Since silicates immersed in aqueous solutions show a surface charge which is a function of pH, it is of primary importance to study the influence of this parameter on the adsorption of collector ions acting as Strong electrolytes in the pH range where they are utilized. The aim of this present paper is to determine by studying electrokinetic phenomena and recovery curves effectuated with a cationic collector and a anionic collector, the nature of the normal adsorbate-adsorbent interaction. Tables 1 and 2 sum up part of the results previously obtained'H11 for the determination of the point of zero charge of the silicate studied by the streaming potential method. Throughout the remainder of this paper, the surface charge will be considered positive for all values of pH below the point

Jan 1, 1971

SUDBURY ore processed by International Nickel Co. of Canada Ltd. was recovered for many years as two mill concentrates, one primarily of copper, and the other mixed pentlandite-pyrrhotite, But, Since iron content of the nickeliferous pyrrhotite concentrate was ten times its nickel value, capacity of smelting was limited by the need for slagging the excess iron. A process for recovering the iron con- tent was developed after some years of research and a $20-million plant was constructed to employ the new method. Built near Copper Cliff, Ont., the plant started operation early in 1956, scheduled for separate treatment of 365,000 tons of pyrrhotite each year. It is only the first unit of an installation which will have a capacity of more than 1 million tons per year of pyrrhotite. By early 1958, production totaled more than 200,000 long tons of 68 pct Fe pellets containing 0.003 pct P, 1.5 pct SiO2, 0.01 pct S, and 0.15 pct Ni.

Jan 8, 1958

By M. E. Gershon

A mixed-integer formulation of the mine scheduling problem is discussed and applied for the purpose of optimizing both the mine production sequencing and the mill blending and processing problem simultaneously. Previous attempts at solving these problem separately, although successful, fail to take into account the interrelationships between these problems. Project structure selves as the outline of this paper Generalized in its organization, this concept is useful for long, intermediate, and short range scheduling. Actual applications that show the concept also is applicable to mining a variety of ore are mentioned.

Jan 1, 1984

By Duane E. Eubanks, David B. McDonald

The anticipated growth of western coal production over the next decade is expected to add approximately 274.3 million t/y (302.4 million stpy) to US capacity. The increased output, coming from both new mines and expansion of existing facilities, promises to bring with it a new set of problems for mine planners.

Jan 8, 1976

By Shiou-Chuan Sun

SHIOU-CHUAN SUN (author's reply).-Thanks are extended to Professor Hassialis for his recognition of the usefulness of a new tool, the cataphoretic cell, as an adjunct to the bubble machine and the abstraction test. His questions concerning adsorption, dielectric constant, floatability, activation, and depression are interesting and worthy of discussion. I According to Mueller,28 it is questionable that any of the present formulas gives absolute values of zeta potentials which are completely accurate. The problem is further complicated by the question" of whether the "dielectric constant" has any meaning at all for such a microscopically thin layer. With these in mind, the results in this paper should be considered in the relative sense as a first approximation and not as absolute quantities. Adsorption Referring to item a of Fig. 8, the dielectric constant and the viscosity of the xanthate solutions are the same for galena, sphalerite and quartz. If dielectric constant and viscosity (but not the adsorption) were the first-order variable of the cataphoretic system, as claimed by Professor Hassialis, then the magnitudes of zeta coefficient of galena, spha)erite and quartz would have been similar to each other. These are not. The big difference of zeta coefficient of these three minerals in the same xanthate solutions is not altogether unjustified to be attributed to their difference in adsorption of xanthate ions. This is supported by the results of chemical abstraction tests reported by Ince.14 Again, the big difference of zeta coefficient between wollastonite, calcite, and fluorite in the same laurylamine hydrochloride solutions (p. 118, Figs. 58, 59, and 60 of ref. r5) also indicates that the cataphoretic system is not governed chiefly by the dielectric constant. Beside the data shown in Fig. 8, other experimental evidences15 which support the idea of correlation between adsorption and zeta coefficient are: (I) there is a qualitative parallelism between the zeta coefficient curve and the chemical abstraction curve of sphalerite in solutions of various concentrations of sodium cyanide, (2) there is a qualitative parallelism between the zeta coefficient curve and the chemical abstraction curve of sphalerite in solutions of constant concentration of copper sulphate at different pH values, and (3) there is a qualitative parallelism between zeta coefficient curve and chemical abstraction curve of quartz in solutions with constant concentration of barium chloride at different pH values. The above mentioned experimental results are generally in agreement with Gouy's double layer theory,1-5 and support this idea that the concentration and the kind of ions adsorbed at the mineral surface and in the adjacent surrounding liquid chiefly govern the electrokinetic phenomena. Dielectric constant and viscosity of the liquid medium may be of somewhat lesser importance. It follows that the correlation between the coefficient and adsorption as claimed in this paper is justified. Dielectric Constant The term "dielectric constant " was first introduced into the electrokinetic equations by Perrin.30 In a footnote of his publication he states that Holmheltz has forgotten to include the dielectric constant. The conversion of the moment29 to the zeta potential involves an additional difficulty and confusion not involved for the moment, namely, assigning a value to the dielectric coefficient. This is conventionally assumed to be constant and equal to the dielectric constant of the bulk liquid. 21 The published literature 10, 12 indicates that the values of dielectric constant for dilute chemical solutions have been assumed as those of pure water.

Jan 1, 1947

By Robert E. Thurmond

DISCOVERY of a commercial ore deposit has resulted from a program emphasizing geophysical techniques and concentrating upon exploration of alluvial-covered areas. United Geophysical Co. selected these areas as offering the best possibility of success, for here the surface evidence of ore deposits has been hidden from the eyes of prospector and geologist alike. Pima mining district, Pima County, Arizona, was selected for initial exploration. The project was successful in that a commercial ore deposit was discovered and proved through drilling and extensive underground development. A limited region of activity was chosen and library research was begun on available economic and regional geological publications relating to the mining districts. Field reconnaissance of those districts which seemed to hold exploration possibilities provided a general picture and ascertained the existence of alluvial-covered areas of interest. At the conclusion of the reconnaissance trips all data obtained were compiled, and the district which seemed to present the best exploration possibilities was selected by statistical methods. The statistical summary was based on the following considerations: Geological Factors: 1—type of intrusive, P—presence of favorable host rocks, 3—apparent intensity of mineralization, and 4—presence of favorable structure in covered or unexplored areas. Economic Factors: 1—past production from district or mine; 2—size, shape, grade, and type of ore deposit in the district; 3—ease of acquiring mineral rights; and 4—general development facility. Exploration Favorability Factors: 1—results to be anticipated from geological methods alone; 2—application of geophysical methods, namely, topographic conditions, surface interference, depth-size relation, physical property contrasts as related to ores or controlling structural features; and 3—drilling factors. Admittedly, many of these, factors do not lend themselves to absolute evaluation, but relative evaluation, subject to inaccuracies of personal judgment, is always possible. A relative scale from 1 to 10 was established for every factor, representing varying degrees of favorability. For each district a numerical evaluation of each factor was established and a numerical total determined. The obvious advantage of this scheme is that a more concise summation can be presented by numerical means than can be achieved by descriptive means. After a district had been selected as favorable, the first step was to carry out more detailed geological and economic studies to narrow down the areas of interest. The second step was to compile all available geological data from publications and add to these data by mapping where necessary. Geological interpretation and projection of structural or other control into covered or unexplored areas was made whenever logical. To determine the possibilities of geophysical application and to select a geophysical method, physical property contrasts were related to mineral assemblages and/or structural control. If geophysics seemed applicable, trial profiles were run crossing the area normal to the strike and spaced

Jan 1, 1955

By Kenneth C. Vincent, A. M. Gaudin

In a study1 of the action of amyl xan-thate on chalcocite in water suspension, it was found that if the xanthate is added in relatively large quantity the xanthate group can be accounted for in three forms: (1) as xanthate ion remaining in water, (2) as benzene-soluble cuprous xanthate on the chalcocite, (3) as a benzene-insoluble coating on the chalcocite. Reduction in the amount of xanthate added leads to disappearance of form I then of form 2. With minute quantities of added xanthate, substantially all the reagent is of the "unleachable" kind. Yet this unleach-able xanthate can be dissolved by pyridine to form a soluble cuprous xanthate complex, and it is sufficient in effectiveness to make chalcocite flotable even if insufficient in quantity to form a complete mono-molecular film on the mineral. In that study it was also found that chalcocite abstracts cuprous xanthate from benzene so1ution, in what may (or may not) be a case of molecular adsorption. It seemed desirable, therefore, to study further the "unleachable" xanthate on the chalcocite, and particularly to ascertain whether it is formed as a result of the benzene leach or is actually formed during the conditioning of chalcocite in aqueous xanthate solution. A 'splendid tool to make such studies has recently been perfected; that is, the use of radioactive spies or tracer atoms. With this tool, it was thought possible to answer the problem stated above, but, unfortunately, this did not prove to be true. Answer to the flotation question was clouded by the existence of rapid and selective diffusion of copper atoms in the solid mineral—a phenomenon that was totally unexpected yet remains interesting and perhaps important. Method of Radioactive Spies The method of radioactive spies is discussed in many places. Two convenient references are the article by Evans2 and the book by pollard and Davidson.3 The method was first developed by van Hevesy and paneth in 1013, when only natural radioactive isotopes were available. These isotopes are few in number, and so the method remained limited in scope. Recently the synthesis of over 350 active isotopes of all the known stable chemical elements4 has opened widely expanded possibilities for the method, A fundamental tenet of the method is that a radioactive atom and a nonradio-active atom are exactly alike until disintegration of the radioactive atom. Then, by its sudden death, the spy reveals its location. The relative abundance of spies at various locations makes it possible to ascertain the relative abundance of the corresponding nonradioactive atoms at the same times and locations. A second fundamental tenet of the method of radioactive tracers is that the radioactivity lies in the nucleus of the atom: transfer of radioactivity from one

Jan 1, 1947

By Kenneth C. Vincent, A. M. Gaudin

In a study1 of the action of amyl xan-thate on chalcocite in water suspension, it was found that if the xanthate is added in relatively large quantity the xanthate group can be accounted for in three forms: (1) as xanthate ion remaining in water, (2) as benzene-soluble cuprous xanthate on the chalcocite, (3) as a benzene-insoluble coating on the chalcocite. Reduction in the amount of xanthate added leads to disappearance of form I then of form 2. With minute quantities of added xanthate, substantially all the reagent is of the "unleachable" kind. Yet this unleach-able xanthate can be dissolved by pyridine to form a soluble cuprous xanthate complex, and it is sufficient in effectiveness to make chalcocite flotable even if insufficient in quantity to form a complete mono-molecular film on the mineral. In that study it was also found that chalcocite abstracts cuprous xanthate from benzene so1ution, in what may (or may not) be a case of molecular adsorption. It seemed desirable, therefore, to study further the "unleachable" xanthate on the chalcocite, and particularly to ascertain whether it is formed as a result of the benzene leach or is actually formed during the conditioning of chalcocite in aqueous xanthate solution. A 'splendid tool to make such studies has recently been perfected; that is, the use of radioactive spies or tracer atoms. With this tool, it was thought possible to answer the problem stated above, but, unfortunately, this did not prove to be true. Answer to the flotation question was clouded by the existence of rapid and selective diffusion of copper atoms in the solid mineral—a phenomenon that was totally unexpected yet remains interesting and perhaps important. Method of Radioactive Spies The method of radioactive spies is discussed in many places. Two convenient references are the article by Evans2 and the book by pollard and Davidson.3 The method was first developed by van Hevesy and paneth in 1013, when only natural radioactive isotopes were available. These isotopes are few in number, and so the method remained limited in scope. Recently the synthesis of over 350 active isotopes of all the known stable chemical elements4 has opened widely expanded possibilities for the method, A fundamental tenet of the method is that a radioactive atom and a nonradio-active atom are exactly alike until disintegration of the radioactive atom. Then, by its sudden death, the spy reveals its location. The relative abundance of spies at various locations makes it possible to ascertain the relative abundance of the corresponding nonradioactive atoms at the same times and locations. A second fundamental tenet of the method of radioactive tracers is that the radioactivity lies in the nucleus of the atom: transfer of radioactivity from one

Jan 1, 1947

By Fred P. Peters

At first glance this paper may seem unique among those comprising this symposium on designing for powder metallurgy, since it is evidently concerned with everything but Powder metallurgy. This paradox mill be at once resolved, however, when the real Purpose of the symposium meeting is understood—to present factually and objectively the things that can and cannot he done with powder-metallurgy methods, and especially to set forth with brutal frankness the limitations of Powder metallurgy, so that costly over-enthusiasm and misapplication may be prevented. Since much of powder metallurgy's future development (and many of its present disappointments) has been in competition with other and long-established methods of fabricating parts, it is easy to see that its true competitive possibilities in any given case cannot be accurately appraised without rudimentary knowledge of what the competition can do. This paper, therefore, presents a few reminders of things you all know—a background to be kept in mind as you examine the data on each of their specialties given by the authors of the papers that follow. From the standpoint of the design engineer powder metallurgy is often in Competition with one or more of the following: sand casting, die casting, permanent-mold casting, precision investment casting, ma- chined bar stock, screw-machine parts, cold-heading, drop-forging, and stamping and drawing. We will here briefly discuss each of these individually, and set forth so, rough (and therefore dangerous) generalizations about its competitive position, especially with respect to powder metallurgy. Sand Casting Sand-casting of small parts is sometimes an inexpensive method of manufacture, for its raw-material costs (i,e., for gray iron) are the lowest of the various methods and it involves the use of no tools and dies of jewelry quality. its design flexibility— that is, the ability to make complicated, cored and undercut parts in one piece—is about the highest of the competing processes and in this respect it can do many things that are impossible by powder metallurgy. For small castings its production rates may be higher, by using multi-impression molds, than can be achieved with parts of the same size by powder metallurgy. But its labor charges for melting, pouring, patternmaking and molding are comparatively high and the waste it entails in gates and risers is always considerable. Tolerances of sand castings are wide (+1/6 to 1/32 in- per in.) and where precision approaching that of powder metallurgy is required sand castings must be machined to final size, thus increasing their cost. Steel sand castings are more expensive and less precise than iron, and nonferrous the most costly of all.

Jan 1, 1945

By R. N. Upadhyay, M. Maleki, I. Fatt

Conventional laboratory core analysis tests on samples of two limestone reservoir rocks indicate that about 20 per cent of PV is in dead-end pores. These tests (electric logging formation factor, mercury injection capillary pressure and miscible displacement) were carried out on 1/4-in. diameter test plugs. Test results show a clear dilference between these samples and sandstone or homogeneous limestone reservoir rock. Although the amount of dead-end pore space can be only roughly estimated, the presence of such pore space seems clearly indicated. Pressure transient studies also show presence of deadend PV. Although they do not give quantitative results, pressure transient data yield a reasonable estimate of the size of the neck connecting dead-end pores to the main flow channels. INTRODUCTION Equations conventionally used to describe reservoir flow behavior contain the implicit assumption that all connected pore spaces contributed to both porosity and permeability. Several authors3-7 have pointed out the changes in pressure transient behavior and in electric log interpretation that may result if this assumption is incorrect and, instead, dead-end or cul-de-sac pores are present. There is a need for laboratory tests that can detect presence of dead-end pores in core samples. With such information on hand the petroleum engineer can make more rational use of the mathematical tools now available for analysis of reservoir flow behavior. This paper describes laboratory studies designed to detect and, if possible, give a quantitative measure of dead-end PV in laboratory-size core plugs. Three reservoir rocks were used, two of which were limestones suspected of having deadend pore spaces and a well-known sandstone, used as a comparison standard, in which there is believed to be little or no dead-end pore space. All the studies were designed to measure the natural dead-end PV; i.e., the pore space which is dead-ended because of rock structure. During multiphase flow in a rock without dead-end pores, some parts of one of the phases can become surrounded by the other, thereby giving (for certain flow behavior) an effective dead-end pV8,9. Such behavior will not be described here.

Jan 1, 1967

By E. A. Anderson

THE copper-zinc phase equilibrium diagram has been the sub-ject of many investigations. Until recently, however, the boundary of the terminal solid solution of copper in zinc (eta) has not been thoroughly investigated. This paper reports determinations of the solid solubility of copper in zinc at temperatures from 100° to 400° C., the course of the liquidus and solidus for the eta solid solution and determinations of the peritectic temperature and peritectic point for the reaction between epsilon and the melt to form eta. The liquidus of the eta phase was determined by thermal analysis and the solidus by the microscopical examination of specimens quenched from temperatures above and below the solidus. The temperature of the peritectic horizontal was obtained by thermal analysis and the com-position at the peritectic point was determined by extrapolation of the solid solubility boundary of the eta phase to the peritectic horizontal. The solid solubility boundary of the eta solid solution was investigated very carefully. Particular care was used to achieve equilibrium in the alloys at each temperature selected. The X-ray, electrical con-ductivity and microscopical methods were used in determining the solid solubility limits. The X-ray method measures the changes in the solvent lattice with increasing solute content and in this manner locates the composition of the alloy at which no further change in the solvent lattice takes place, the limit of solid solubility. The method of electrical conductivity measures the conductivity of the alloys of a graded series of compositions, whereby the solubility limit is indicated by a discontinuity in the conductivity-

Jan 1, 1934

By W. H. Bassett

ABOUT twenty-five years ago the copper industry had outgrown the Lake Superior production. The electrolytic copper producers had- their process well in hand and the industry was well started in the use of electrolytic copper, both for working into wire and sheet, and for the making of alloys. The trade knew that some brands of copper made good material and that other brands did not. There came together a group of men-a refiner, a rolling-mill man, and a manufacturer of electrical machinery-each of them desiring to know why there was a difference and what .it was. Much investigation was done with wire bars and cakes which involved ' chemical analysis, metallographic examination, physical tests and electrical tests. To find the influence of different kinds of copper in making brass 200 carloads of ingots were made into ,eyelet brass under careful observation; each carload was carefully analyzed and tested before used. The alloy was made and rolled under standard conditions and the results recorded.

Jan 1, 1924

By M. S. Smani, P. Blazy, J. M. Cases

Investigations on the beneficiation of sedimentary Moroccan phosphate ores are reported in four separate parts. The first discusses electrochemical phenomena at the solid-aqueous solution interface for minerals of the apatite group. In the second part, the electrochemical properties of the calcareous gangue associated with the phosphate ore are investigated. The flotation of calcite and phosphate oölites, using both anionic and cationic collectors, is discussed in the third part. It is shown that selective recovery could be obtained for precise concentrations of collectors and pH ranges. Results of work aimed at optimizing depression of phosphate oölites during inverse flotation of the carbonate gangue with sodium oleate are reported in Part 4.

Jan 1, 1976

By C. G. Dunn

According to a recently suggested effect of silicon on the re recrystallization textures of high-purity Fe-Si alloys with (111)[112] type rolling textures, the recrystallization texture for a rolled (110)[001] oriented iron crystal probably should be entirely different from that of a (110)[001] oriented 3 pct Si-Fe crystal. Comparative studies of iron and 3 pct Si-Fe crystals, however, show that both have (110)[Ool] recrystallization textures when the rolling textures are the (111)[112] type after reductions in thickness of about 70 pct. Qualitatively the results from the iron crystal are like those of polycrystalline high-purity 3 pct Si-Fe and not like polycrys-talline high-purity iron. The large effect previously noted probably involves unknown impurities or processing variables rather than silicon itself. Some problems on experimental and analytical procedure for a spherical X-ray specimen, which was machined from a laminated composite of sheet specimens, are treated in the Appendix. A possible strong effect of silicon on the textures produced in cold-rolled high-purity Fe-Si (HPFe-Si) alloys during primary recrystallization and normal grain growth was suggested in a recent paper.' All the textures were far from the random-orientation type, but that of iron, or of Fe-Si alloys of low silicon composition, was entirely different from the texture of 3 pct Si-Fe. The same effect was noted for the textures obtained prior to normal grain growth, i.e., for primary recrystallization.2 It is the main purpose of the present paper to provide some clarification of this silicon effect. All the HPFe-Si alloys from zero to 3 pct Si, which were rolled by two or more stages separated by anneals, developed (111)[112] type rolling textures.2 Thus, there was no effect of silicon on the rolling textures. Earlier, Gensamer and Mehl3 also found no effect of silicon on the rolling textures of Fe-Si alloys; they obtained the Kurdjum.ow and Sachs (K-S) rolling texture for iron,4 which is characterized as the three ideal components: (100)[011], (112)[li0], and (111)[112]. There is a difference between the HPFe-Si multiple-stage rolling texture and the K-S single-stage rolling texture, but this is a variable processing effect. Of interest here is the fact that the recrystallization textures from (111) [llZ] type rolling textures were different depending on the amount of silicon in the alloy. There was a relatively strong (110) [001] component in the recrystallization texture of HP 3 pct Si-Fe5,8,2 but no such component in HP 0.6 pct Si-Fe, for example; the recrystallization texture for the latter was two (111) [110] type components and a (111) fiber component 1,2 Several publications have shown that a strong (110) [001] recrystallization texture is derivable from a (111) [112] type rolling texture for 3 pct Si-Fe crystals reduced in thickness by about 70 pct.7-10 Furthermore it appears that the strongest of these (110) [001] recrystallization textures occurred when the orientation of the crystal prior to rolling was (110) [001].7 Barrett and evensoon11 found that the rolling texture of a (110)[001] oriented iron crystal was (111) [llj]. Accordingly, it seemed desirable to determine whether a (110) [001] oriented iron crystal, upon rolling and annealing, would behave like the 3 pct Si-Fe crystal (or the polycrystalline HP 3 pct Si-Fe) and thus produce a (110) [001] recrystallization texture contrary to the suggested silicon effect, or would behave like the polycry stalline HP iron or HP 0.6 pct Si-Fe and thus produce (lll) [110] type components in agreement with a silicon effect. Briefly, the idea here involves the use of more precisely defined textures to obtain if possible better control of important variables that affect the recrystallization process. PROCEDURE A (110) oriented crystal of Ferrovac "E" iron (99.9 pct pure) was prepared in sheet form 0.080 in. thick with the [001] direction parallel to the long dimension of the specimen.'' This crystal was etched to 0.073 in. thickness (to remove some small included grains) and then was cold rolled in a 6-in.-diam mill to a final thickness of 0.022 in. The rolling was unidirectional except for an inadvertent reversal at 0.061 in. thickness. At this thickness, and also at 0.040 in., the rolling was interrupted for transmission Laue photographs. Molybdenum Ka-radiation filtered with zirconium was used in a transmission method1' to obtain the cold-rolled (110) pole figure. The sample was a 0.002-in.-thick section taken from the central region of the 0.022-in.-thick cold-rolled crystal. For the primary recrystallization study, cold-rolled samples were etched from 0.022 to 0.021 in. thick and annealed in hydrogen at 850°C. Primary recrystallization to a fine-grained structure, Fig. 1, was obtained in a 5-min anneal. Eleven sheets after

Jan 1, 1963